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https://issues.apache.org/jira/browse/HDFS-8341?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14537733#comment-14537733
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Hari Sekhon commented on HDFS-8341:
-----------------------------------
I had to move several thousand blocks by hand via scripting which was a
significant proportion of the total blocks given that I had only put some
limited amount of expendible data on the archive tier for testing. Given the
dimensions of the data I'm certain it wasn't only successive blocks for one
given file.
The command was looping on the same block, which also implies it never
proceeded to try to move the blocks of the other files, hence the large number
of blocks left behind and not moved back to the regular disk tier.
> HDFS mover stuck in loop after failing to move block, doesn't move rest of
> blocks, can't get data back off decommissioning external storage tier as a
> result
> ------------------------------------------------------------------------------------------------------------------------------------------------------------
>
> Key: HDFS-8341
> URL: https://issues.apache.org/jira/browse/HDFS-8341
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: balancer & mover
> Affects Versions: 2.6.0
> Environment: HDP 2.2
> Reporter: Hari Sekhon
> Assignee: surendra singh lilhore
> Priority: Blocker
>
> HDFS mover gets stuck looping on a block that fails to move and doesn't
> migrate the rest of the blocks.
> This is preventing recovery of data from a decomissioning external storage
> tier used for archive (we've had problems with that proprietary "hyperscale"
> storage product which is why a couple blocks here and there have checksum
> problems or premature eof as shown below), but this should not prevent moving
> all the other blocks to recover our data:
> {code}hdfs mover -p /apps/hive/warehouse/<custom_scrubbed>
> 15/05/07 14:52:50 INFO mover.Mover: namenodes =
> {hdfs://nameservice1=[/apps/hive/warehouse/<custom_scrubbed>]}
> 15/05/07 14:52:51 INFO balancer.KeyManager: Block token params received from
> NN: update interval=10hrs, 0sec, token lifetime=10hrs, 0sec
> 15/05/07 14:52:51 INFO block.BlockTokenSecretManager: Setting block keys
> 15/05/07 14:52:51 INFO balancer.KeyManager: Update block keys every 2hrs,
> 30mins, 0sec
> 15/05/07 14:52:52 INFO block.BlockTokenSecretManager: Setting block keys
> 15/05/07 14:52:52 INFO net.NetworkTopology: Adding a new node:
> /default-rack/<ip>:1019
> 15/05/07 14:52:52 INFO net.NetworkTopology: Adding a new node:
> /default-rack/<ip>:1019
> 15/05/07 14:52:52 INFO net.NetworkTopology: Adding a new node:
> /default-rack/<ip>:1019
> 15/05/07 14:52:52 INFO net.NetworkTopology: Adding a new node:
> /default-rack/<ip>:1019
> 15/05/07 14:52:52 INFO net.NetworkTopology: Adding a new node:
> /default-rack/<ip>:1019
> 15/05/07 14:52:52 INFO net.NetworkTopology: Adding a new node:
> /default-rack/<ip>:1019
> 15/05/07 14:52:52 WARN balancer.Dispatcher: Failed to move
> blk_1075156654_1438349 with size=134217728 from <ip>:1019:ARCHIVE to
> <ip>:1019:DISK through <ip>:1019: block move is failed: opReplaceBlock
> BP-120244285-<ip>-1417023863606:blk_1075156654_1438349 received exception
> java.io.EOFException: Premature EOF: no length prefix available
> <NOW IT STARTS LOOPING ON SAME BLOCK>
> 15/05/07 14:53:31 INFO net.NetworkTopology: Adding a new node:
> /default-rack/<ip>:1019
> 15/05/07 14:53:31 INFO net.NetworkTopology: Adding a new node:
> /default-rack/<ip>:1019
> 15/05/07 14:53:31 INFO net.NetworkTopology: Adding a new node:
> /default-rack/<ip>:1019
> 15/05/07 14:53:31 INFO net.NetworkTopology: Adding a new node:
> /default-rack/<ip>:1019
> 15/05/07 14:53:31 INFO net.NetworkTopology: Adding a new node:
> /default-rack/<ip>:1019
> 15/05/07 14:53:31 INFO net.NetworkTopology: Adding a new node:
> /default-rack/<ip>:1019
> 15/05/07 14:53:31 WARN balancer.Dispatcher: Failed to move
> blk_1075156654_1438349 with size=134217728 from <ip>:1019:ARCHIVE to
> <ip>:1019:DISK through <ip>:1019: block move is failed: opReplaceBlock
> BP-120244285-<ip>-1417023863606:blk_1075156654_1438349 received exception
> java.io.EOFException: Premature EOF: no length prefix available
> ...<repeat indefinitely>...
> {code}
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